Fabrication of High-performance LiCoO2 Cathode Materials by Regulated Resource Regeneration from Spent Lithium-Ion Batteries

The refabrication of lithium-ion batteries (LIBs) from the value-added metals of spent LIBs is a promising strategy to mitigate current environmental and resource availability issues. However, the preparation of high-performance LiCoO2 (LCO) by the closed-loop reutilization of LCO resources remains challenging. This study proposes a novel recycling strategy that involves separating Li and Co from spent LIBs in a single step, followed by the closed-loop refabrication of LCO cathode materials using the regenerated resources with Ti doping and multi-stage calcination. The results showed that 99.5 pct of the Li was leached, and Co was recovered as a precipitated complex (Co3O4 precursor) in an environmentally friendly tartaric acid/H2O2 medium under the optimized leaching conditions. The leaching behavior of Li conformed to the Avrami equation model, and the associated activation energy was calculated to be 21.98 kJ/mol at temperatures of 313-353 K. The discharge capacity of the regenerated LCO (R-LCO) subjected to two-stage calcination (204.39 mAh/g) was significantly higher than that of the LCO subjected to one-stage calcination (187.11 mAh/g) at 0.1 C in the voltage range of 3.0-4.58 V. Ti doping was found to have little effect on the structure and morphology of the regenerated Co3O4, although it imparted R-LCO with a higher crystallinity and superior cycling performance. The LCO with Ti doping (Ti/Co molar ratio = 0.005:1) synthesized via two-stage calcination exhibited an initial coulombic efficiency of 93.65 pct and maintained a capacity retention of 93.8 pct after the 50th cycle. This work provides a promising method for resynthesizing high-performance cathode materials via the closed-loop recovery of spent LIB materials.